HARD and soft real time system

hard real-time system (immediate real-time system)

A hard real-time system (also known as an immediate real-time system) is hardware or software that must operate within the confines of a stringent deadline. The application may be considered to have failed if it does not complete its function within the allotted time span. Examples of hard real-time systems include components of pacemakers, anti-lock brakes and aircraft control systems.

Hard real-time = Pacemakers, Airplane control systems
Soft real-time = Live Video Streaming








http://www.ece.cmu.edu/~koopman/des_s99/real_time/
http://whatis.techtarget.com/definition/hard-real-time-system-immediate-real-time-system

http://www.le.ac.uk/eg/fss1/real%20time.htm